This application requests continuing support for a training program that has been active for 30 years. This program supports training for two predoctoral and two postdoctoral fellows (M.D., Ph.D. and M.D./Ph.D.) per year in the fundamentals of renal and epithelial cell function ranging from the organismal to cellular, subcellular and molecular levels. The principal aim of this program is to prepare qualified and motivated persons for academic careers with special emphasis and expertise in renal and cellular physiology and molecular pathogenesis. Areas of interest in which training is offered include ion transport and their pharmacological and physiological regulation, cellular actions of mineralocorticoids on ion transport, cytoskeletal structure, intracellular trafficking of ion channels and vesicles, the cellular and molecular biology of molecular motors, molecular pathogenesis and renal epithelial cell - bacteria interaction. Predoctoral students are enrolled as Ph.D. candidates in graduate programs in the departments of Physiology, Pharmacology, and the Molecular and Cellular Biology Program, which includes the departments of Biochemistry, Biological Sciences and Microbiology and Immunology. During the first two years, these students follow a schedule of required courses and laboratory rotations. Graduate students then initiate original research leading to a doctoral thesis. Postdoctoral fellows are engaged in research under the tutelage of a faculty sponsor but have their research experience broadened by regular interactions with other faculty and fellows through conferences, seminars, and courses in renal physiology, signal transduction, and cell and molecular biology. In addition, the program faculty and trainees interact closely with faculty and students in other NIH sponsored training programs at Dartmouth. Postdoctoral trainees with either the M.D. or Ph.D. degree are chosen on the basis of their motivation for a long-term career, prior training, references, and academic standing. Final selection for all trainees follows a personal visit and a successful interview with faculty members. The primary training is within the departments of Physiology, Pharmacology, Biochemistry, Biological Sciences and Microbiology at Dartmouth Medical School and Dartmouth College. The ten full-time faculty have their own fully equipped research laboratories, have extensive experience training students, are highly interactive, and all of our faculty (except emeritus) have active grants. Other facilities include several Cores (e.g., Molecular Biology and Proteomics), offices for trainees, classrooms, libraries, on-line computing facilities, and the resources of Dartmouth College and the Dartmouth-Hitchcock Medical Center.